Inflammation and late-life depressive symptoms

Background Low-level systemic inflammation has been associated with late-life depressive symptoms. Whether individuals with higher inflammation derive preventive benefit from low-dose aspirin therapy is unknown. Methods We performed a post-hoc analysis of the ASPiring in Reducing Events in the Elderly (ASPREE) randomised, double-blind, placebo-controlled trial. Baseline C-reactive protein (hsCRP) was measured in plasma and depressive symptoms were assessed annually using the Center for Epidemiologic Studies Depression 10 Scale (CES-D-10) with elevated symptoms defined as CES-D-10 ≥ 8. Participants with elevated depressive symptoms at baseline were excluded. We fitted population-averaged logistic generalised estimating equation models adjusted for baseline sociodemographic and lifestyle covariates, including an hsCRP × treatment interaction to test effect modification by aspirin. Results Higher baseline hsCRP was associated with increased odds of elevated depressive symptoms during follow-up (OR 1.07 per SD increase in hsCRP, 95% CI 1.03–1.11). Low-dose aspirin allocation did not modify the hsCRP-depressive symptoms association (interaction OR 1.02, 95% CI 0.94–1.10). Findings were similar after additional adjustment for comorbidity and other covariates. Conclusions In community-dwelling older adults during the ASPREE randomised trial period, higher baseline hsCRP was modestly associated with elevated depressive symptoms. There was no evidence that low-dose aspirin was associated with reduced risk of depressive symptoms among participants with higher baseline inflammation.